Glow in the dark ulcers

This issue’s digest commentary is on the use of an autofluorescence imaging (AFI) device, MolecuLight i:X; in the management of diabetic foot ulcers (DFU). 

It is well known that DFU frequently become chronic. One confounding reason is the presence and role of wound flora and biofilm formation. Clinically, it is also often difficult to determine the extent of bacterial wound contamination. 

This AFI device is claimed to be able to help determine detrimental levels of bacterial wound contaminants. This was a randomised controlled trial pilot study to investigate and determine the role and effectiveness of AFI in managing DFU. 

Bacterial cell walls contain porphyrins and pyoverdines, which at certain concentrations will automatically fluoresce red or cyan (Pseudomonas species), with collagen and elastin emitting green fluorescence under certain wavelengths of violet light (590–690 nm). 

The aims of this 12-week study were to determine healing rates, the influence of AFI upon clinical treatment decision-making and quality of life markers. In all, 56 subjects with non-infected DFU were randomised to either a control (CG) or intervention group (IG). Standard wound care was given to both groups, with the intervention group having AFI used every 4 weeks. The influence on decision-making was deemed positive if antimicrobial dressings and/or further debridement were initiated following a positive AFI result. The groups were well matched for demographics, diabetes parameters, SINBAD scores and comorbidities. The IG had slightly smaller wound size (0.37 versus 0.54 cm²), but a longer duration of 20 weeks versus 15 weeks (interquartile range). Healing occurred at 12 weeks in 45% (n=13/29) and 22.2% (n=6/27) in the IG and CG groups, respectively. Mean wound size reduction at 12 weeks was 91.3% and 72.8% in the IG and CG groups respectively. Cast walker or TCC offloading occurred in 34.5%(n=10) versus 22.2%(n=6) in IG and CG respectively. 

Positive AFI influenced treatment change overall on 40.9% of subject visits, dropping from 56.3% at baseline to 27.3% at week 8. Adverse events occurred in 13.8%(n=4) and 22.2% (n=6) in IG and CG respectively. No difference was found in quality of life between either group. 

This study is underpowered, thus it is difficult to draw firm conclusions, but its data suggest that AFI may be a useful tool in helping to determine antimicrobial interventions during DFU treatments and may prevent chronicity. 

Further powered studies are needed to further investigate the efficacy of this AFI device.